1. Field of the Invention
The present invention relates to a thermal insulation detector. More specifically, the invention relates to a mechanical thermal insulation detector for a non-insulated ceiling (non-IC) recessed lighting fixture.
2. Description of the Related Art
Recessed lights are typically used where low hanging fixtures are not desirable or where focused lighting on a specific area is desirable. They are typically used in personal or commercial properties in living areas, kitchens, work spaces, halls or various types of areas in order to concealed lighting over both large and focused areas. These downlights can sometimes rotate about a vertical axis and/or tilt about a horizontal axis to a desired wall-wash angle in order to illuminate a desired area.
Recessed light fixtures fall into two categories: insulated ceiling (IC) and non-insulated ceiling (non-IC). Insulated ceiling fixtures allow placement of insulation against the metal fixture frame or housing such as in an attic floor. Non-insulated ceiling fixtures require a minimal clearance between the housing and insulation, for fire safety, so as not to trap heat commensurate with National Electric Code.
State of the art temperature sensors are typically input voltage specific. That is, at a specific desirable input voltage, the system will dissipate heat fast enough to operate at an allowable temperature. However, the addition of insulation to a non-IC fixture will not allow dissipation fast enough so that as the temperature increases a thermal sensor will open, inhibiting operation of the fixture.
Contrary to these temperature sensors, current recessed luminaires are being designed to operate at various input voltages. Generally, the temperature sensors designed for a single input voltage will not function properly at voltages other than the specific voltage they are designed for. This causes a problem when used with power supplies and ballasts that self-adjust to accept multiple input voltage levels. As a result, the fixture will either fail to operate or the detection means may not be accurate.
UL requires thermal insulation detection for non-insulated ceiling luminaires. It would be desirable to provide a thermal insulation detector which operates with a wide range of operating voltages and detects the presence of thermal insulation by mechanical force or pressure exerted by the thermal insulation to inhibit operation of the luminaire. Such thermal insulation detector should overcome these and other problems to detect insulation about non-IC fixtures. This insulation detector would accept a wide range of input voltages and overcome problems associated with known thermal detection or thermal overload systems.